571 research outputs found
Improving Polypharmacy and Medication Review in the Elderly
Polypharmacy in elderly patients increases risk of adverse drug events, which can cause health and functional impairment, necessitating considerate medication review. Many patients do not remember the names or doses of their medications when asked in the office. To successfully deprescribe and avoid adverse drug events, we need accurate medication information. By asking elderly patients to bring all of their medications to each visit, we can ensure the most accurate information possible.https://scholarworks.uvm.edu/fmclerk/2003/thumbnail.jp
Orbital evolution under the action of fast interstellar gas flow with non-constant drag coefficient
The acceleration of a spherical dust particle caused by an interstellar gas
flow depends on the drag coefficient which is, for the given particle and flow
of interstellar gas, a specific function of the relative speed of the dust
particle with respect to the interstellar gas. We investigate the motion of a
dust particle in the case when the acceleration caused by the interstellar gas
flow represent a small perturbation to the gravity of a central star. We
present the secular time derivatives of the Keplerian orbital elements of the
dust particle under the action of the acceleration from the interstellar gas
flow for arbitrary orbit orientation. The semimajor axis of the dust particle
is a decreasing function of time for an interstellar gas flow acceleration with
constant drag coefficient and also for such an acceleration with the linearly
variable drag coefficient. The decrease of the semimajor axis is slower for the
interstellar gas flow acceleration with the variable drag coefficient. The
minimal and maximal values of the decrease of the semimajor axis are
determined. In the planar case, when the interstellar gas flow velocity lies in
the orbital plane of the particle, the orbit always approaches the position
with the maximal value of the transversal component of the interstellar gas
flow velocity vector measured at perihelion.
The properties of the orbital evolution derived from the secular time
derivatives are consistent with numerical integrations of the equation of
motion. If the interstellar gas flow speed is much larger than the speed of the
dust particle, then the linear approximation of dependence of the drag
coefficient on the relative speed of the dust particle with respect to the
interstellar gas is usable for practically arbitrary (no close to zero) values
of the molecular speed ratios (Mach numbers).Comment: 12 pages, 6 figures, 2 equations added in v
The L1 Cell Adhesion Molecule Is Essential for Topographic Mapping of Retinal Axons
The retinocollicular projection is a preferred axon guidance pathway for investigating molecular mechanisms of synaptic targeting in the mammalian CNS. Here we identify a previously unrecognized role of the L1 cell adhesion molecule in topographic mapping of retinal ganglion cell (RGC) axons to their targets in the mouse superior colliculus (SC). L1 was transiently expressed on RGC axons during axon growth and targeting. DiI labeling of retinal axons revealed that temporal axons of L1-minus mice bypassed correct target locations in the anterior SC, forming termination zones at incorrect posterior sites, which were often skewed along the mediolateral axis. During development of the retinotopic map L1-minus temporal axons extended across the anteroposterior axis of the SC like wild-type axons but failed to arborize at normal anterior target sites. L1-minus RGC axons exhibited normal crossing at the optic chiasm and fasciculation of the optic nerve. Results suggest that retinal axons require the function of L1 in addition to repellent EphA guidance receptors to achieve proper topographic mapping
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Fermentative Approaches to Hydrogen Production
A PowerPoint presentation given as part of the 2005 Hydrogen Program Review, May 23-26, 2005, in Washington, D.C
GCIRS16SW: a massive eclipsing binary in the Galactic Center
We report on the spectroscopic monitoring of GCIRS16SW, an Ofpe/WN9 star and
LBV candidate in the central parsec of the Galaxy. SINFONI observations show
strong daily spectroscopic changes in the K band. Radial velocities are derived
from the HeI 2.112 um line complex and vary regularly with a period of 19.45
days, indicating that the star is most likely an eclipsing binary. Under
various assumptions, we are able to derive a mass of ~ 50 Msun for each
component.Comment: 4 pages, 4 figures, ApJ Letters accepte
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Hydrogen from Water in a Novel Recombinant Oxygen-Tolerant Cyanobacterial System
The objective of this report is to develop an O{sub 2}-tolerant cyanobacterial system for continuous light-driven H{sub 2} production from water. The overall goal is to produce a cyanobacterial recombinant to produce H{sub 2} continuously
The M Dwarf GJ 436 and its Neptune-Mass Planet
We determine stellar parameters for the M dwarf GJ 436 that hosts a
Neptune-mass planet. We employ primarily spectral modeling at low and high
resolution, examining the agreement between model and observed optical spectra
of five comparison stars of type, M0-M3. Modeling high resolution optical
spectra suffers from uncertainties in TiO transitions, affecting the predicted
strengths of both atomic and molecular lines in M dwarfs. The determination of
Teff, gravity, and metallicity from optical spectra remains at ~10%. As
molecules provide opacity both in lines and as an effective continuum,
determing molecular transition parameters remains a challenge facing models
such as the PHOENIX series, best verified with high resolution and
spectrophotometric spectra. Our analysis of GJ 436 yields an effective
temperature of Teff = 3350 +/- 300 K and a mass of 0.44 Msun. New Doppler
measurements for GJ 436 with a precision of 3 m/s taken during 6 years improve
the Keplerian model of the planet, giving a minimum mass, M sin i = 0.0713 Mjup
= 22.6 Mearth, period, P = 2.6439 d, and e = 0.16 +/- 0.02. The noncircular
orbit contrasts with the tidally circularized orbits of all close-in
exoplanets, implying either ongoing pumping of eccentricity by a more distant
companion, or a higher Q value for this low-mass planet. The velocities indeed
reveal a long term trend, indicating a possible distant companion.Comment: 27 pages, 7 figures, accepted to PAS
CO\u3csub\u3e2\u3c/sub\u3e-Fixing One-Carbon Metabolism in a Cellulose-Degrading Bacterium \u3cem\u3eClostridium thermocellum\u3c/em\u3e
Clostridium thermocellum can ferment cellulosic biomass to formate and other end products, including CO2. This organism lacks formate dehydrogenase (Fdh), which catalyzes the reduction of CO2 to formate. However, feeding the bacterium 13C-bicarbonate and cellobiose followed by NMR analysis showed the production of 13C-formate in C. thermocellum culture, indicating the presence of an uncharacterized pathway capable of converting CO2 to formate. Combining genomic and experimental data, we demonstrated that the conversion of CO2 to formate serves as a CO2 entry point into the reductive one-carbon (C1) metabolism, and internalizes CO2 via two biochemical reactions: the reversed pyruvate: ferredoxin oxidoreductase (rPFOR), which incorporates CO2 using acetyl-CoA as a substrate and generates pyruvate, and pyruvate- formate lyase (PFL) converting pyruvate to formate and acetyl-CoA. We analyzed the labeling patterns of proteinogenic amino acids in individual deletions of all five putative PFOR mutants and in a PFL deletion mutant. We identified two enzymes acting as rPFOR, confirmed the dual activities of rPFOR and PFL crucial for CO2 uptake, and provided physical evidence of a distinct in vivo “rPFOR-PFL shunt” to reduce CO2 to formate while circumventing the lack of Fdh. Such a pathway precedes CO2 fixation via the reductive C1 metabolic pathway in C. thermocellum. These findings demonstrated the metabolic versatility of C. thermocellum, which is thought of as primarily a cellulosic heterotroph but is shown here to be endowed with the ability to fix CO2 as well
Characterization of the protein kinase activity of avian sarcoma virus src gene product.
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